Analysis of local quench antenna signals

This document gives a brief description of the Local Quench Antennas (LQA) with the goal to help understanding the mechanism used to record and localize a quench in the LHC dipole magnets. The analysis of the signals of the main voltage taps is reported in detail. This analysis is necessary to get the information about the approximate quench location of the quench: aperture, and pole. It gives also the range of time in which the quench started and developed allowing filtering the LQA data. A readable display of the signals is presented. The principle to obtain the longitudinal location of the quench starting point along the magnet head is explained. It is presented how to work out the origin of the quench, based on the information, between sides and blocks of the same pole. A criterion, based on the quench propagation velocity, provides the information about the quenched layer based on probability calculations. Finally the method is applied to investigate the quench origin of the magnet MB2420 and the results are reported at the end of this document.